8 : 8 = 1       16 : 8 = 2       24 : 8 = 3       32 : 8 = 4       40 : 8 = 5       48 : 8 = 6       56 : 8 = 7       64 : 8 = 8       72 : 8 = 9       80 : 8 = 10

8 : 8 = 1

16 : 8 = 2

24 : 8 = 3

32 : 8 = 4

40 : 8 = 5

48 : 8 = 6

56 : 8 = 7

64 : 8 = 8

72 : 8 = 9

80 : 8 = 10

a) \(600m+300m=900m\)

b) \(700cm+20cm=720cm\)

c)\(20dm+500dm=520dm\)

d)\(1000km-200km=800km\)

900m,520dm,720cm,1200km

12 : 1/4 = 16 x 3

1/2 x 10 + 8 + 6 =19

50 + 1/2 x 5 = 75

Lớp 2 học cái này rùi sao ????????????????????????????

45 ban nha

Đề sai nha bạn

Sửa đề

Tính:1+2+3+4+5+6+7+8+10

  = (1+9)+(2+8)+(3+7)+(4+6)+5+10

  =   10   +   10  +  10   +  10   +   15

 =       10 x 4 +15

=              55

\(\frac{2}{3}+\frac{9}{6}=\frac{4}{6}+\frac{9}{6}=\frac{4+9}{6}=\frac{13}{6}\)

\(\frac{4}{5}+\frac{25}{15}=\frac{12}{15}+\frac{25}{15}=\frac{12+25}{15}=\frac{37}{15}\)

\(\frac{20}{10}+\frac{8}{2}=2+4=6\)

\(\frac{2}{3}+\frac{9}{6}=\frac{2}{3}+\frac{3}{2}=\frac{4+9}{6}=\frac{15}{6}=\frac{5}{2}\)

\(\frac{4}{5}+\frac{25}{16}=\frac{64+125}{80}=\frac{189}{80}\)

1-1=0

1+3+4+5+4+8+2+9+4+6x0=0

1 - 1 = 0

1 + 3 + 4 + 5 + 4 + 8 + 2 + 9 + 4 + 6 x 0 = 0

\(1+2+3+4+5+6+7+8+9=45\)\(45\)

Bằng 45

8 + 11 = 19

mà theo mk

1 + 4 = 5

2 + 5 = 7

3 + 6 = 9

8 + 11 = 19